Pooled Safety Analysis of Single-Agent Lurbinectedin in Patients With Advanced Solid Tumours

BACKGROUND

Lurbinectedin was approved by FDA and other health regulatory agencies for treating adults with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy. Safety profile at approved dose (3.2 mg/m2 every 3 weeks) was acceptable and manageable in 105 adult SCLC patients from a phase II basket trial. This study analyses safety data from several solid tumours treated at the lurbinectedin-approved dose.

METHODS

Data were pooled from 554 patients: 335 from all nine tumour-specific cohorts of the phase II basket trial and 219 from a randomised phase III trial (CORAIL) in platinum-resistant ovarian cancer. Events and laboratory abnormalities were graded using NCI-CTCAE v.4.

RESULTS

Most common tumours were ovarian (n = 219, 40%), SCLC (n = 105, 19%) and endometrial (n = 73, 13%). Transient haematological laboratory abnormalities were the most frequent grade 3 or more events: neutropenia (41%), leukopenia (30%), anaemia (17%) and thrombocytopenia (10%). Most common treatment-emergent non-haematological events (any grade) were transient transaminase increases (alanine aminotransferase [66%], aspartate aminotransferase [53%]), fatigue (63%), nausea (57%), constipation (32%), vomiting (30%) and decreased appetite (25%). Dose reductions were mostly due to haematological toxicities, but most patients (79%) remained on full lurbinectedin dose. Serious events mostly consisted of haematological disorders. Eighteen treatment discontinuations (3%) and seven deaths (1%) were due to treatment-related events.

CONCLUSIONS

This analysis confirms a manageable safety profile for lurbinectedin in patients with advanced solid tumours. Findings are consistent with those reported in patients with relapsed SCLC, Ewing sarcoma, germline BRCA1/2 metastatic breast cancer, neuroendocrine tumours and ovarian cancer.

Combination lurbinectedin and doxorubicin versus physician's choice of chemotherapy in patients with relapsed small-cell lung cancer (ATLANTIS): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

Lurbinectedin is a synthetic marine-derived anticancer agent that acts as a selective inhibitor of oncogenic transcription. Lurbinectedin monotherapy (3·2 mg/m² every 3 weeks) received accelerated approval from the US Food and Drug Administration on the basis of efficacy in patients with small-cell lung cancer (SCLC) who relapsed after first-line platinum-based chemotherapy. The ATLANTIS trial assessed the efficacy and safety of combination lurbinectedin and the anthracycline doxorubicin as second-line treatment for SCLC.

METHODS

In this phase 3, open-label, randomised study, adult patients aged 18 years or older with SCLC who relapsed after platinum-based chemotherapy were recruited from 135 hospitals across North America, South America, Europe, and the Middle East. Patients were randomly assigned (1:1) centrally by dynamic allocation to intravenous lurbinectedin 2·0 mg/m² plus doxorubicin 40·0 mg/m² administered on day 1 of 21-day cycles or physician's choice of control therapy (intravenous topotecan 1·5 mg/m² on days 1-5 of 21-day cycles; or intravenous cyclophosphamide 1000 mg/m², doxorubicin 45·0 mg/m², and vincristine 2·0 mg on day 1 of 21-day cycles [CAV]) administered until disease progression or unacceptable toxicity. Primary granulocyte-colony stimulating factor prophylaxis was mandatory in both treatment groups. Neither patients nor clinicians were masked to treatment allocation, but the independent review committee, which assessed outcomes, was masked to patients' treatment allocation. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02566993, and with EudraCT, 2015-001641-89, and is complete.

FINDINGS

Between Aug 30, 2016, and Aug 20, 2018, 613 patients were randomly assigned to lurbinectedin plus doxorubicin (n=307) or control (topotecan, n=127; CAV, n=179) and comprised the intention-to-treat population; safety endpoints were assessed in patients who had received any partial or complete study treatment infusions (lurbinectedin plus doxorubicin, n=303; control, n=289). After a median follow-up of 24·1 months (95% CI 21·7-26·3), 303 patients in the lurbinectedin plus doxorubicin group and 289 patients in the control group had discontinued study treatment; progressive disease was the most common reason for discontinuation (213 [70%] patients in the lurbinectedin plus doxorubicin group vs 152 [53%] in the control group). Median overall survival was 8·6 months (95% CI 7·1-9·4) in the lurbinectedin plus doxorubicin group versus 7·6 months (6·6-8·2) in the control group (stratified log-rank p=0·90; hazard ratio 0·97 [95% CI 0·82-1·15], p=0·70). 12 patients died because of treatment-related adverse events: two (<1%) of 303 in the lurbinectedin plus doxorubicin group and ten (3%) of 289 in the control group. 296 (98%) of 303 patients in the lurbinectedin plus doxorubicin group had treatment-emergent adverse events compared with 284 (98%) of 289 patients in the control group; treatment-related adverse events occurred in 268 (88%) patients in the lurbinectedin plus doxorubicin group and 266 (92%) patients in the control group. Grade 3 or worse haematological adverse events were less frequent in the lurbinectedin plus doxorubicin group than the control group (anaemia, 57 [19%] of 302 patients in the lurbinectedin plus doxorubicin group vs 110 [38%] of 288 in the control group; neutropenia, 112 [37%] vs 200 [69%]; thrombocytopenia, 42 [14%] vs 90 [31%]). The frequency of treatment-related adverse events leading to treatment discontinuation was lower in the lurbinectedin plus doxorubicin group than in the control group (26 [9%] of 303 patients in the lurbinectedin plus doxorubicin group vs 47 [16%] of 289 in the control group).

INTERPRETATION

Combination therapy with lurbinectedin plus doxorubicin did not improve overall survival versus control in patients with relapsed SCLC. However, lurbinectedin plus doxorubicin showed a favourable haematological safety profile compared with control.

FUNDING

PharmaMar.

Antitumor activity of lurbinectedin in combination with oral capecitabine in patients with metastatic breast cancer

BACKGROUND

Preclinical studies showed a synergistic effect for 5-fluorouracil and lurbinectedin against solid tumors. This phase I trial evaluated a combination of capecitabine plus lurbinectedin in patients with selected advanced solid tumors. Results in patients with relapsed metastatic breast cancer (MBC) are described.

PATIENTS AND METHODS

Patients received capecitabine daily on day (D)1-D14 combined with lurbinectedin on D1, D8 or D1 every 3 weeks (q3w) intravenously, following a standard 3 + 3 escalation design and expansion at the recommended dose (RD).

RESULTS

Of the 81 enrolled patients, 28 had relapsed MBC: 20 with hormone receptor (HR)-positive tumors and 8 with triple-negative tumors; 3 treated in the D1,D8 schedule and 25 in the D1 schedule. The RD was capecitabine 1650 mg/m² daily on D1-D14 plus lurbinectedin 2.2 mg/m² on D1 q3w. Sixteen confirmed responses and two prolonged disease stabilizations (≥6 months) were observed [overall response rate (ORR)/clinical benefit rate (CBR) = 57%/64% at all dose levels; 47%/60% at the RD]. Twelve responses and both prolonged stabilizations occurred in HR-positive tumors (ORR/CBR = 60%/70% at all dose levels, 56%/78% at the RD). Four responses were found in triple-negative tumors (ORR and CBR = 50% at all dose levels; 33% at the RD). Myelotoxicity was reversible and manageable at the RD; most non-hematological toxicities were mild/moderate. No episodes of febrile neutropenia or severe palmar-plantar erythrodysesthesia syndrome occurred. No major pharmacokinetic drug-drug interaction was found between lurbinectedin, capecitabine or capecitabine metabolites.

CONCLUSIONS

The capecitabine/lurbinectedin combination showed encouraging clinical activity in relapsed MBC, especially in HR-positive tumors. Toxicity was manageable at the RD. Further development is warranted in relapsed MBC.

Antitumor Activity of Lurbinectedin, a Selective Inhibitor of Oncogene Transcription, in Patients with Relapsed Ewing Sarcoma: Results of a Basket Phase II Study

PURPOSE

Lurbinectedin suppresses the oncogenic transcription factor EWS-FLI1 through relocalization to the nucleolus, and delays tumor growth in mice bearing Ewing sarcoma xenografts. On the basis of this rationale, lurbinectedin was evaluated in patients with relapsed Ewing sarcoma.

PATIENTS AND METHODS

This open-label, single-arm, Basket phase II trial included a cohort of 28 treated adult patients with confirmed Ewing sarcoma, measurable disease as per Response Evaluation Criteria In Solid Tumors (RECIST) v.1.1, Eastern Cooperative Oncology Group performance status ≤2, adequate organ function, no central nervous system metastasis, and pretreated with ≤2 chemotherapy lines for metastatic/recurrent disease. Patients received lurbinectedin 3.2 mg/m2 as a 1-hour infusion every 3 weeks. Primary endpoint was overall response rate (ORR) as per RECIST v.1.1. Secondary endpoints included time-to-event parameters and safety profile.

RESULTS

ORR was 14.3% [95% confidence interval (CI), 4.0%-32.7%], with median duration of response of 4.2 months (95% CI, 2.9-5.5 months). Median progression-free survival was 2.7 months (95% CI, 1.4-4.3 months), clinical benefit rate was 39.3%, and disease control rate was 57.1%. With 39% censoring, median overall survival was 12.0 months (95% CI, 8.5-18.5 months). Most common grade 3/4 adverse events were neutropenia (57%), anemia, thrombocytopenia, and treatment-related febrile neutropenia (14% each). No deaths or discontinuations were due to toxicity.

CONCLUSIONS

Lurbinectedin was active in the treatment of relapsed Ewing sarcoma and had a manageable safety profile. Lurbinectedin could represent a valuable addition to therapies for Ewing sarcoma, and is currently being evaluated in combination with irinotecan in advanced Ewing sarcoma in a phase Ib/II trial.

Phase I study of lurbinectedin in combination with weekly paclitaxel with or without bevacizumab in patients with advanced solid tumors

Lurbinectedin and paclitaxel showed synergism in preclinical studies and have non-completely overlapping toxicity profiles. This phase I trial evaluated a combination of paclitaxel and lurbinectedin with/without bevacizumab in advanced tumors. This trial was divided into Group A, which evaluated weekly paclitaxel (60 or 80 mg) plus lurbinectedin (3.0-5.0 mg flat dose [FD] or 2.2 mg/m²) every 3 weeks in advanced solid tumors; and Group B, which evaluated bevacizumab (BEV, 15 mg/kg) added to the recommended dose (RD) defined in Group A in advanced epithelial ovarian or non-small cell lung cancer (NSCLC). 67 patients (A, n = 55; B, n = 12) were treated. The RD was paclitaxel 80 mg/m² on Day (D)1,D8 plus lurbinectedin 2.2 mg/m² on D1. At this RD, myelotoxicity was reversible and manageable, and most non-hematological toxicities were mild/moderate. Adding BEV did not notably change tolerability. Twenty-five confirmed responses were observed: 20/51 evaluable patients in Group A (overall response rate [ORR] = 39% at all dose levels and at the RD), and 5/10 evaluable patients in Group B (ORR = 50%). Most responders had breast (n = 7/12 patients), small cell lung (SCLC) (n = 5/7), epithelial ovarian (n = 3/9) and endometrial cancer (n = 3/11) in Group A, and epithelial ovarian (n = 3/4) and NSCLC (n = 2/6) in Group B. Clinical benefit rate was 61% in Group A (58% at the RD), and 90% in Group B. No major pharmacokinetic drug-drug interactions were observed. Paclitaxel/lurbinectedin and paclitaxel/lurbinectedin/BEV are feasible combinations. Further development is warranted of paclitaxel/lurbinectedin in SCLC, breast, and endometrial cancer, and of paclitaxel/lurbinectedin/BEV in epithelial ovarian cancer.

First-in-human study of PM14 in patients with advanced solid tumors

3078

Background: PM14 is a new chemical entity that forms DNA adducts which specifically inhibit RNA synthesis and block active transcription of protein-coding genes. Antitumor activity has been demonstrated in vitro in several cell lines (e.g. lung, kidney, prostate), and in vivo in mice bearing xenografted human-derived tumors (soft tissue sarcoma, small cell lung cancer, ovarian, gastric, breast and renal cancer). Methods: Open-label, dose-escalating, phase I trial of PM14 administered as a 3-hour infusion i.v. every 3 weeks (q3wk) in patients (pts) with advanced solid tumors, adequate organ function and ECOG PS score of 0-1. Two schedules were explored: Schedule A (Day 1 [D1], Day 8 [D8]) and Schedule B (D1). Results: 37 pts were treated (Schedule A/B: 28/9 pts). Baseline characteristics of pts (A/B): median age 56/47 years; male 57%/56%; ECOG PS 0: 57%/56%; median of prior lines (range): 3 (1-8)/4 (1-10). Most common tumor types (A + B): STS (n=7 pts), ovarian (n=6), pancreatic (n=4), prostate cancer (n=3). The maximum tolerated dose was 4.5 mg/m2 for A (dose-limiting toxicities [DLTs]: D8 omission due to lack of recovery of lab parameters for re-treatment [n=2 pts]) and 5.6 mg/m2 (DLTs: G4 febrile neutropenia [n=1], G4 transaminase increase [n=1]) for B. The recommended dose (RD) was 3.0 mg/m2 on D1,D8 (A), and 4.5 mg/m2 on D1 (B). No DLTs were present at the RDs. Most common toxicities were hematological abnormalities and transaminase increase. Main toxicities at the RDs are shown below. Antitumor activity comprised stable disease ≥4 months in 7 heavily pretreated pts (6 in A; 1 in B) at all dose levels. Linear pharmacokinetics were observed for PM14 at tested doses (0.25-5.6 mg/m²), with geometric mean (CV%) total plasma clearance 5.9 L/h (88%), volume of distribution 128 L (81%) and median (range) terminal half-life 15.9 h (7.5-34.3 h). Less than 1.6% of administered dose was recovered in urine. Conclusions: RDs were determined for two PM14 schedules in pts with advanced solid tumors. At the RDs, PM14 is well tolerated and has a manageable safety profile. An expansion phase in specific tumor types, with an optional Bayesian continual reassessment method for RD fine-tuning, is ongoing with both schedules.[Table: see text]

Efficacy and safety of lurbinectedin and doxorubicin in relapsed small cell lung cancer. Results from an expansion cohort of a phase I study

Background A phase I study found remarkable activity and manageable toxicity for doxorubicin (bolus) plus lurbinectedin (1-h intravenous [i.v.] infusion) on Day 1 every three weeks (q3wk) as second-line therapy in relapsed small cell lung cancer (SCLC). An expansion cohort further evaluated this combination. Patients and methods Twenty-eight patients with relapsed SCLC after no more than one line of cytotoxic-containing chemotherapy were treated: 18 (64%) with sensitive disease (chemotherapy-free interval [CTFI] ≥90 days) and ten (36%) with resistant disease (CTFI <90 days; including six with refractory disease [CTFI ≤30 days]). Results Ten patients showed confirmed response (overall response rate [ORR] = 36%); median progression-free survival (PFS) = 3.3 months; median overall survival (OS) = 7.9 months. ORR was 50% in sensitive disease (median PFS = 5.7 months; median OS = 11.5 months) and 10% in resistant disease (median PFS = 1.3 months; median OS = 4.6 months). The main toxicity was transient and reversible myelosuppression. Treatment-related non-hematological events (fatigue, nausea, decreased appetite, vomiting, alopecia) were mostly mild or moderate. Conclusion Doxorubicin 40 mg/m² and lurbinectedin 2.0 mg/m² on Day 1 q3wk has shown noteworthy activity in relapsed SCLC and a manageable safety profile. The combination is being evaluated as second-line therapy for SCLC in an ongoing, randomized phase III trial. Clinical trial registration www.ClinicalTrials.gov code: NCT01970540. Date of registration: 22 October, 2013.

Lurbinectedin (LUR) in combination with Irinotecan (IRI) in patients (pts) with advanced solid tumors: Updated results from a phase Ib-II trial

3514

Background: LUR is a novel agent that exerts antitumor activity through inhibition of trans-activated transcription and modulation of tumor microenvironment. Preclinical synergism/additivity in combination with IRI has been reported, thus prompting the conduct of this clinical trial. Methods: Phase Ib-II trial to evaluate escalating doses of LUR on Day (D) 1 plus a fixed dose of IRI 75 mg/m2 on D1 and D8 every 3 weeks (q3w) in pts with advanced solid tumors (+/- G-CSF, if dose-limiting toxicities [DLTs] were neutropenia). Starting dose was LUR 1.0 m/m2 + IRI 75 mg/m2. Results: 77 pts have been treated to date at 5 dose levels, 51 of them at the recommended dose (RD). Baseline characteristics of all 77 pts were: 48% females, 68% ECOG PS=1; median age 57 years (range, 19-75 years); median of 2 prior lines (range, 0−4 lines). The maximum tolerated dose (MTD) was LUR 2.4 mg/m2 + IRI 75 mg/m2 with G-CSF, and the RD was LUR 2.0 mg/m2 + IRI 75 mg/m2 with G-CSF. DLTs in Cycle 1 occurred in 2/3 evaluable pts at the MTD and 3/13 evaluable pts at the RD, and comprised omission of IRI D8 infusion due to grade (G) 3/4 neutropenia (n=3 pts) or G2-4 thrombocytopenia (n=2). At the RD (n=51), common G1/2 non-hematological toxicities were nausea, vomiting, fatigue, diarrhea, anorexia and neuropathy. G3 non-hematological toxicities (diarrhea 10%, fatigue 10%) and G3/4 hematological abnormalities (neutropenia 49%, thrombocytopenia 10%) were transient. Conclusions: The combination of LUR and IRI had acceptable tolerance, with no unexpected toxicities. Transient myelosuppression was dose-limiting. The RD is LUR 2.0 mg/m2 on D1 + IRI 75 mg/m2 on D1 and D8 q3w with G-CSF. Antitumor activity was observed at the RD in SCLC pts, as well as in endometrial carcinoma pts. Hints of activity were also observed in STS pts. Updated results will be presented. Clinical trial information: NCT02611024 . [Table: see text]

Pooled safety analysis of single-agent lurbinectedin versus topotecan (Results from a randomized phase III trial CORAIL and a phase II basket trial)

3635

Background: Lurbinectedin (L), an inhibitor of active transcription, has shown activity in second-line (2L) small cell lung cancer (SCLC) (ASCO 2019). Topotecan (T) is the only approved drug in 2L SCLC and is also used in platinum resistant ovarian cancer (PROC). Methods: This pooled safety analysis includes data from 554 patients (pts) treated with L at 3.2 mg/m2 Day 1 q3wk 1-h (no primary prophylaxis with G-CSF required): 335 with selected solid tumors (9 indications, including 105 pts with SCLC) from a phase II Basket study and 219 with PROC in the phase III CORAIL study. An indirect exploratory comparison (pooled data from CORAIL + Basket) and a direct comparison (data from CORAIL) of L vs. T are presented. Results: Most common adverse events with L were grade 1/2 fatigue, nausea and vomiting. Treatment-related (L/T): dose reductions: 22.9/48.3%, delays: 25.8/52.9%, grade ≥3 serious adverse events (SAEs): 15.0/32.2%, discontinuations: 3.2/5.7%, deaths: 1.3/1.5%, G-CSF use: 23.8/70.1%, and transfusions: 15.9/52.9%. Conclusions: Lurbinectedin has a predictable and manageable safety profile. A significant safety advantage was observed when lurbinectedin was compared with topotecan in the CORAIL trial in terms of hematological toxicities. With the limitations of indirect comparisons, in the pooled safety analysis, fewer lurbinectedin-treated pts had severe hematological toxicities, SAEs, dose adjustments, treatment discontinuations and use of supportive treatments than topotecan-treated pts. Clinical trial information: NCT02421588 and NCT02454972 . [Table: see text]

Antitumor activity of lurbinectedin (PM01183) and doxorubicin in relapsed small-cell lung cancer: results from a phase I study

BACKGROUND

Lurbinectedin (PM01183) has synergistic antitumor activity when combined with doxorubicin in mice with xenografted tumors. This phase I trial determined the recommended dose (RD) of doxorubicin (bolus) and PM01183 (1-h intravenous infusion) on day 1 every 3 weeks (q3wk), and obtained preliminary evidence of antitumor activity for this combination in small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Patients with advanced solid tumors received doxorubicin and PM01183 following a standard dose escalation design and expansion at the RD. Twenty-seven patients had relapsed SCLC: 12 with sensitive disease (platinum-free interval ≥90 days) and 15 with resistant disease (platinum-free interval <90 days).

RESULTS

Doxorubicin 50 mg/m2 and PM01183 4.0 mg flat dose was the RD. In relapsed SCLC, treatment tolerance at the RD was manageable. Transient and reversible myelosuppression (including neutropenia, thrombocytopenia, and febrile neutropenia) was the main toxicity, managed with dose adjustment and colony-stimulating factors. Fatigue (79%), nausea/vomiting (58%), decreased appetite (53%), mucositis (53%), alopecia (42%), diarrhea/constipation (42%), and asymptomatic creatinine (68%) and transaminase increases (alanine aminotransferase 42%; aspartate aminotransferase 32%) were common, and mostly mild or moderate. Complete (n = 2, 8%) and partial response (n = 13, 50%) occurred in relapsed SCLC, mostly at the RD. Response rates at second line were 91.7% in sensitive disease [median progression-free survival (PFS)=5.8 months] and 33.3% in resistant disease (median PFS = 3.5 months). At third line, response rate was 20.0% (median PFS = 1.2 months), all in resistant disease.

CONCLUSION

Doxorubicin 50 mg/m2 and PM01183 4.0 mg flat dose on day 1 q3wk has shown remarkable activity, mainly in second line, with manageable tolerance in relapsed SCLC, leading to further evaluation of this combination within an ongoing phase III trial.

Activity of trabectedin in germline BRCA1/2-mutated metastatic breast cancer: results of an international first-in-class phase II study

BACKGROUND

Breast cancer is a heterogeneous disease defined by both germline and somatic abnormalities. In preclinical models, tumors carrying homologous recombination defects are highly sensitive to trabectedin. This phase II trial evaluated the efficacy and safety of trabectedin in BRCA1/2 germline mutation carriers with pretreated metastatic breast cancer (MBC).

PATIENTS AND METHODS

Trabectedin 1.3 mg/m(2) as a 3-h i.v. infusion was administered every 3 weeks until progression or intolerance. The primary efficacy end point was the objective response rate (ORR) as per RECIST. Secondary efficacy end points comprised time-to-event end points, and changes in tumor volume and expression of tumor marker CA15.3. Safety was evaluated using the NCI-CTCAE.

RESULTS

Forty BRCA1/2 germline mutation carriers with MBC were included. Confirmed partial response (PR) occurred in 6 of 35 assessable patients [ORR = 17%; 95% confidence interval (CI) 7% to 34%] and lasted 1.4-6.8 months. Median PFS was 3.9 months (95% CI 1.6-5.5 months). Eight patients (21%) showed changes in tumor volume, and 14 (40%) a clinical benefit. Trabectedin-related adverse events were generally mild/moderate, the most common being fatigue, nausea, constipation and anorexia. Severe laboratory abnormalities (neutropenia, transaminase increases) were mostly transient and noncumulative, and were managed by dose adjustments.

CONCLUSIONS

With the caveat of the limited patient number, trabectedin monotherapy showed activity and was well tolerated in heavily pretreated MBC patients selected for germline BRCA mutation. These results prompt further evaluation of trabectedin alone or combined with other specific drugs in this indication.

CLINICALTRIALSGOV

NCT00580112.

First-in-human phase I study of Lurbinectedin (PM01183) in patients with advanced solid tumors

PURPOSE

Lurbinectedin (PM01183) binds covalently to DNA and has broad activity against tumor cell lines. This first-in-human phase I study evaluated dose-limiting toxicities (DLT) and defined a phase II recommended dose for PM01183 as a 1-hour intravenous infusion every three weeks (q3wk).

EXPERIMENTAL DESIGN

Thirty-one patients with advanced solid tumors received escalating doses of PM01183 following an accelerated titration design.

RESULTS

PM01183 was safely escalated over 200-fold, from 0.02 to 5.0 mg/m(2). Dose doubling was utilized, requiring 15 patients and nine dose levels to identify DLT. The recommended dose was 4.0 mg/m(2), with one of 15 patients having DLT (grade 4 thrombocytopenia). Clearance was independent of body surface area; thus, a flat dose of 7.0 mg was used during expansion. Myelosuppression, mostly grade 4 neutropenia, occurred in 40% of patients but was transient and manageable, and none was febrile. All other toxicity was mild and fatigue, nausea and vomiting were the most common at the recommended dose. Pharmacokinetic parameters showed high interindividual variation, though linearity was observed. At or above the recommended dose, the myelosuppressive effect was significantly associated with the area under the concentration-time curve from time zero to infinity (white blood cells, P = 0.0007; absolute neutrophil count, P = 0.016). A partial response was observed in one patient with pancreatic adenocarcinoma at the recommended dose.

CONCLUSION

A flat dose of 7.0 mg is the recommended dose for PM01183 as a 1-hour infusion q3wk. This dose is tolerated and active. Severe neutropenia occurred at this dose, although it was transient and with no clinical consequences in this study.

Multicenter phase II study of plitidepsin in patients with relapsed/refractory non-Hodgkin's lymphoma

This phase II clinical trial evaluated the efficacy, safety and pharmacokinetics of plitidepsin 3.2 mg/m(2) administered as a 1-hour intravenous infusion weekly on days 1, 8 and 15 every 4 weeks in 67 adult patients with relapsed/refractory aggressive non-Hodgkin's lymphoma. Patients were divided into two cohorts: those with non-cutaneous peripheral T-cell lymphoma (n=34) and those with other lymphomas (n=33). Efficacy was evaluated using the International Working Group criteria (1999). Of the 29 evaluable patients with non-cutaneous peripheral T-cell lymphoma, six had a response (overall response rate 20.7%; 95% confidence interval, 8.0%-39.7%), including two complete responses and four partial responses. No responses occurred in the 30 evaluable patients with other lymphomas (including 27 B-cell lymphomas). The most common plitidepsin-related adverse events were nausea, fatigue and myalgia (grade 3 in <10% of cases). Severe laboratory abnormalities (lymphopenia, anemia, thrombocytopenia, and increased levels of transaminase and creatine phosphokinase) were transient and easily managed by plitidepsin dose adjustments. The pharmacokinetic profile did not differ from that previously reported in patients with solid tumors. In conclusion, plitidepsin monotherapy has clinical activity in relapsed/refractory T-cell lymphomas. Combinations of plitidepsin with other chemotherapeutic drugs deserve further evaluation in patients with non-cutaneous peripheral T-cell lymphoma. (clinicaltrials.gov identifier: NCT00884286).

Multicenter phase II study of trabectedin in patients with metastatic castration-resistant prostate cancer

BACKGROUND

This multicenter phase II trial evaluated the efficacy and safety of trabectedin in metastatic castration-resistant prostate cancer (CRPC).

PATIENTS AND METHODS

Two schedules were evaluated in three cohorts: weekly as 3-h i.v. infusion at 0.58 mg/m(2) for 3 out of 4 weeks (Cohort A, n = 33), and every 3 weeks (q3wk) as 24-h infusion at 1.5 mg/m(2) (Cohort B1, n = 5) and 1.2 mg/m(2) (Cohort B2, n = 20). The primary end point was prostate-specific antigen (PSA) response; secondary end points included safety, tolerability and time to progression (TTP).

RESULTS

Trabectedin resulted in PSA declines ≥ 50% in 12.5% (Cohort A) and 10.5% (Cohort B2) of patients. Among men pretreated with taxane-based chemotherapy, PSA response was 13.6% (Cohort A) and 15.4% (Cohort B2). PSA responses lasted 4.1-8.6 months, and median TTP was 1.5 months (Cohort A) and 1.9 months (Cohort B2). The dose of 1.5 mg/m(2) (approved for soft tissue sarcoma) given as 24-h infusion q3wk was not tolerable in these patients. At 1.2 mg/m(2) q3wk and 0.58 mg/m(2) weekly, the most common adverse events were nausea, fatigue and transient neutropenia and transaminase increase.

CONCLUSIONS

Two different trabectedin schedules showed modest activity in metastatic CRPC. Further studies may require identification of predictive factors of response in prostate cancer.

Chronicles in drug discovery

New brief reports this month describe five timely topics: IDO inhibitors have demonstrated antitumor properties by increasing immune response to tumors and improving chemotherapy effectiveness. One of the current therapeutic efforts for Alzheimer's disease is directed towards blocking the gamma-secretase activity, thus reducing amyloid-beta production. Patients with premature ovarian failure (POF), at present mainly treated with hormone replacement therapy, are belated for novel treatment options. Selective ERbeta agonists are anticipated to emerge as therapeutics for the treatment of various diseases including inflammatory bowel syndrome, endometriosis, dementia and cognitive disorders. Phospholipase A2 inhibitors specific for enzyme isoforms are actively studied as potential antiallergic/antiasthmatic drugs, antiarthritic agents and therapeutics for atherosclerosis.

From transcription to cell surface expression, the induction of MHC class II I-A alpha by interferon-gamma in macrophages is regulated at different levels

Using mouse bone marrow-derived macrophages we determined the role of interferon (IFN)-gamma at the different steps in expression of the I-A alpha chain of MHC class II molecules, from transcription to the cell surface. Levels of transcription, RNA, and protein were low in cells not stimulated with IFN-gamma. Treatment with IFN-gamma for 24 or 48 h induced an increase in mRNA levels (7- and 12-fold) that did not correlate with the increase in transcription (2.5- and 2.7-fold). The half-life of mRNA was not modified by IFN-gamma. These data suggest a block at the level of translation. In fact, IFN-gamma increased ribosome loading, which confirms regulation at the translational level. Treatment with IFN-gamma increased protein synthesis (6-fold after 48 h) and level of expression at the cell surface (3- and 9-fold after 24 and 48 h, respectively). Interestingly, treatment with IFN-gamma also increased the I-A alpha protein half-life from 2 to 6-7 h. This is the first attempt to determine qualitatively and quantitatively the regulation of an inducible gene at all the putative levels of control. The data indicate that IFN-gamma plays a critical role in MHC class II protein expression in macrophages through the regulation of different steps, from transcription to surface expression.

Transcription factors that regulate monocyte/macrophage differentiation

Although all the cells in an organism contain the same genetic information, differences in the cell phenotype arise from the expression of lineage-specific genes. During myelopoiesis, external differentiating signals regulate the expression of a set of transcription factors. The combined action of these transcription factors subsequently determines the expression of myeloid-specific genes and the generation of monocytes and macrophages. In particular, the transcription factor PU.1 has a critical role in this process. We review the contribution of several transcription factors to the control of macrophage development.